In the fiberglass industry, washwater systems remove excess binder from equipment used to form fiberglass insulation products. This binder removal allows the equipment to be operated at optimum efficiency to maximize glass throughput. Cleaning the equipment also reduces damage caused by the buildup of binder, thereby limiting the amount of downtime associated with equipment cleaning, repair, and replacement. The equipment includes items such as forming conveyors, forming hoodwalls, suction boxes, drop out boxes, and forming fans.
Polycarboxylic acid based fiberglass binder resins are commonly used in the glass industry for insulation applications. Polycarboxylic acid based binders can provide advantages in terms of mechanical properties and decreased reliance on environmental control equipment.
One problem with currently available washwater systems is that by using a polyacrylic acid binder, the acidity of the reclaim water increases with the number of cleaning cycles. This acidic reclaim water may corrode the supporting structure and washwater equipment, which is typically made of carbon steel, thereby limiting the equipment's useful life. This acidity in the reclaimed water can also result (1) in added manufacturing costs due to equipment replacement and downtime and (2) in decreased efficiency in the glass manufacturing process which may result in increased manufacturing costs associated with rework and the like.
Various solutions have been attempted to address this corrosion problem. For example, stainless steel can be used to replace the carbon steel in the forming and washwater equipment due to its resistance to corrosion. However, stainless steel equipment is expensive relative to carbon steel equipment.
Another proposed solution is to decrease the number of cycles that reclaim water is passed through the forming equipment. However, this solution leads to increased costs in terms of water usage and wastewater removal and decreases the efficiency of the forming equipment associated with replacing the reclaim water.
It is thus highly desirable to improve the corrosion resistance of forming equipment and washwater equipment.